It is a company which a number of people I know have looked at, but nobody has (as far as I recall) reached any conclusions.
I know of nothing adverse but it does not appear easy to find others who use it - except the chap above who is the 1st one.
S.A.C. is who I am with. The owner, Warren Chmura, died a couple of years ago in a car crash and IIRC his brother (also a US citizen) is now running it. A year ago I had the occassion to speak to an FAA lawyer about various matters (in a seminar) and S.A.C. came up, along with the general matter of N-reg trusts. The lawyer confirmed that they know S.A.C. well and work with them.
On the old question of the future of N-reg trusts the lawyer said they have no plan to stop the use of trusts, except to stop trusts which try to conceal the identity of the beneficial owner ("trustor" is US speak).
So I would check out whether this trust company complies fully with this, and also whether they provide the other services like the 3-yearly re-reg, obtaining radio licenses, passing on correspondence (and how much they charge for that), etc.